The influx of brown seaweed known as sargassum, which has been affecting beaches along Jamaica's north and south coasts, is projected to continue to affect the island's shorelinebut poses no threat to human life or the environment, the National Environment and Planning Agency (NEPA) has advised.
Floating mats of the seaweed have been spotted offshore, with the Hellshire Beach, St Catherine, and Long Bay, Portland, among those affected.
According to NEPA, the mats of seaweed are a natural phenomenon whose origin is linked to the richness of nutrients and high temperatures in the Atlantic Ocean, where it builds up into large mats. These are then transported by ocean currents into the Caribbean, washing up on beaches throughout the region, where they are proving to be a nuisance for tourism interests.
In a release earlier this week, NEPA advised that as the Sargassum rots, it is likely to generate a foul odour and may also attract insects. Leaving it on the beach has proven to be the simplest and least costly solution, and the weed may also be used as mulch or compost once the salt is washed out and it is mixed with manure.
Sargassum is a type of open ocean algae found only in the Atlantic Ocean and provides refuge for migratory species. It is also an essential habitat for some species of fish and invertebrates and provides shelter and food to sea turtles and commercially important fish like tuna.
Additionally, Sargassum plays a role in beach nourishment and is an important element in shoreline stability. However, in excessive amounts, it may result in beach erosion and disrupt the aesthetics of the beach, as is happening in other Caribbean islands.
In cases where it becomes necessary to remove the seaweed from the beach, NEPA has prepared guidelines for such removal as follows:
- Stockpile the seaweed
- Turn the material occasionally to encourage drying and shaking-off of the sand
- Return the sand to the beach
- Dispose of the organic material
The seaweed may also be buried on the beach, and special care should be taken to minimise the amount of sand abstracted when removing sargassum from the beach. The use of heavy compacting equipment on the beach must be specifically permitted by NEPA.